Bench grinder



April 15, 1952 J. E. BERNARD, JR 2,592,785

BENCH GRINDER Filed July 18, 1950 2 SHEETS--SHEET 1 0Z6 20 1T I iiil F5? INVENTOR c/QMEflEJMd, J2:

BY M

ATTORNEYS April 15, 1952 N D, JR 2,592,785

BENCH GRINDER Filed July 18, 1950 2 SHEETS-SHEET 2 ATTORNEY S Patented Apr. 15, 1952 BENCH GRINDER John E. Bernard, Jr., Roanoke, Va., assignor to Walker Machine & Foundry Corporation, Roanoke, Va., a corporation of Virginia Application July 18, 1950, Serial No. 174,522

3 Claims.

This invention relates to a bench grinder.

The general object of the invention is to provide a grinder especially designed for vocational or shop classes in schools or institutions. Special problems attend the use of bench grinders in such environment, in reference to safety, ease of disassembly for cleaning with certainty of correct reassemblage, long life under adverse conditions such as neglect of cleaning, overloading, etc.

One of the more specific objects of the invention is to provide a bench grinder which includes an annular dust seal of unusually great width, freely surrounding the shaft between the inner face plate and the adjacent bearing to protect the latter, said dust seal being fixed to the pillow block in which the bearings are supported, and forming a stop engaged on the one side by the fixed face plate, and on the other by the fixed bearing, to limit endwise movement of the shaft.

Another object of the invention is to provide a bench grinder in which the pillow blocks are each of an axial length to contain the bearing and the dust seal, certain of the bolts which secure the pillow block cap also being passed through the annular dust seal, positively securing it in position.

Still another object of the invention is to provide a bench grinder in which the shaft carries at its opposite ends pairs of face plates of difierent diameter, the smaller of which is of somewhat less diameter than the recess in a sickle wheel, and employed in conjunction with a suitable spacing washer of the same diameter as the smaller face plates, to establish clearance between the frame of the grinder and the adjacent edge of the sickle wheel.

A further object of the invention is to provide a bench grinder of the type described, which, carries a pivotally mounted guard for each wheel.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In the drawings, throughout the several figures of which the same reference characters have been used to denote identical parts:

Figure l is a front elevation of a bench grinder embodying the invention;

Figure 2 is a plan view, partly in section;

Figure 3 is a section taken along the line 3-3 of Figure 2, the guard in swung down position being shown in broken lines;

Figure 4 is a fragmentary elevation, partly in section, of one end of the bench grinder, illustrating its adaptation to the use of the sickle wheel.

Referring now in detail to the several figures, the numeral l represents in general the base of the grinder which has pairs of feet 2 and 3, the feet of a pair being oppositely directed, having their lower faces in a common plane, and having slots 4 at their forward ends to receive bolts for securing the grinder to the bench. The base comprises the web 5, which is in a vertical plane and in bridging relation to the pairs of feet, having stiffening flanges 6 at its ends, and a pair of channel shaped lugs 1, extending forwardly with respect to the front of the base, and of such height as to form between them a recess 8, which is symmetrical with respect to the length of the base. The lugs I are designated to adjustably support work supports 29, and are therefore provided with forwardly extending slots 30, through which the securingbolts for the work supports 29 extend. The work supports have lateral rests 3| which extend in front of the respective wheels 24. At the rear of the work supports and above the web 5 are the pillow blocks 9 and Ill. The pillow blocks are formed at their adjacent ends with semicylindrical bores ll of such size as to freely fit the shaft, and semicylindrical counterbores of larger diameter to receive, in side by side relation, the bearing [2 and dust seal I3. Since the bearing l2 has annular shoulders M on both sides, the face of the pillow block and of the dust seal, which lie adjacent the bearing, are formed with complementary recesses to receive the circular projections defined by said shoulders. The caps 15 and I6 of the pillow blocks are formed with complementary semicylindrical bores and counterbores, and the plane of separation between said caps and pillow blocks is the axial plane of the shaft, parallel to the plane of support of the grinder. The bearing I2 and dust seal l3 are preferably of the same diameter. The pillow blocks and caps constitute journal boxes for the shaft l'l. which closely houses the bearings l2 and dust seals 13.

The shaft H has a middle portion l8 of largest diameter, upon which the pulley I9 is mounted, capable of being moved lengthwise of the middle portion and fixed in any desired position of adjustment by means of the set screw 20. The shaft is of steppeddiameters, the intermediat portion 2| which carries the bearing and pillow block being of slightly less diameter than the middle portion I8, so as to define a shoulder, against which the bearing abuts. The bearings are a pressed fit on the intermediate portion 2! of the shaft, and the dust seal is a free fit on said intermediate portion. Just outside of the pillow block the shaft ll undergoes another reduction in diameter, the terminal portion 22 being of slightly less diameter than the intermediate portion 2|, forming a shoulder against which the inner face plate 23 abuts. The inner face plate is also a pressed fit on the shaft. The grinding wheel 24, which is preferably bushed, is a free fit on the terminal portion 22 of the shaft. The outer face plate 25 is, of course, removable and held in place by a nut 26, which screws on the threaded end of the shaft. Both ends of the grinder are similar, excepting that preferably the face plates 27 and. 2.2, on the right-hand end in Figure 2 are larger than the face plates 23 and 25 shown on the. left end. The latter are made smaller so. as to adapt the grinder to use a special wheel on the left end, as will appear.

Semiannular channel shaped guards 32 are provided, one for each of the grinding wheels, the peripheral portions of the latter rotating within the channels of the guards. At their lower ends the guards are formed with inwardly extendingintegral bosses 33, the ends of which abut lugs 34, extending from the rearward part of the base. Bolts 35 pass through the lugs 34 andv thread into the bosses 33, forming with the lugs 34 pivotal connections for swingably mounting the guards.

Referring now specifically to the dust seals [3, each of these, as has been stated, is a free fit on the shaft ll, and is of unusually great width so that a long leakage path is formed between the shaft and dust seal, through which dust from the grinding wheels must pass before it has access to the bearings. It is well known that the difficulty which dust encounters in moving axially along the interface of two rotating parts, increases geometrically with respect to the axial width of the interface. It is quite important that the endwise movement of the shaft within the pillow block be minimized, largely for the sake of preventing dust being moved in toward the bearing by endwise movement of the shaft. Therefore, the dust sealis provided with apertures 36 and 31 the axes.

of which align with the axes of the holes in the pillow block and cap, through which two of the securing bolts extend, sov that when the cap is tightly screwed in place, the dust seals are immobilized, being fixed very close to the hearings on each side so that substantially no endwise movement of the shaft I1 is possible.

In order to facilitate the correct replacement of the pillow block caps after. they have been removed for cleaning the parts contained in the journal boxes, pairs of dowels 35 and 4B; are provided, rising from the plane surfaces of the pillow blocks and matching with holes in the respective pillow block caps, the position of the dowels and holes being nonidentical for the respective caps so that the caps. will not be inadvertently interchanged, thus they can always be correctly associated with the pillow blocksv to which they belong, avoiding the attempt to force the bolts or strip the threads of the sameif it were attempted to bolt the wrong pillow block cap to the pillow block.

Referring now to Figure 4, this shows a conventional sickle wheel t I which is relatively small in diameter, broad axially, and having deep recesses 42 at the ends of its axis. Without resorting to some expedient, such a wheel could not be employed on a bench grinder without being offset on the shaft a greater distance from the adjacent pillow block than is required for the ordinary grinding wheel 25. By making the face plates. 23. and 25 of suiliciently small diameter to enter the recesses 42, there is room for the sickle wheel on the terminal end 22 of the shaft. However, if the web 43 of the sickle wheel were pushed up toward the fixed face plate 23, the adjacent edge of the sickle wheel would collide with the pillow block 9 and the cap 15. To avoid this, a spacer 44 is employed, this: being a thick metal washer of the same diameter as the face plate 23, and with a central hole large enough to enable it to be slipped upon the shaft. With this spacer in place, the sickle wheel is kept at a definite distance away from the adjacent pillow block and pillow block cap,

While I have in the above description disclosed what I believe to be a preferred and practical embodiment of the. invention, it will be understood by those skilled in the art that the specific details of construction and arrangement of parts, as shown and described, are by way of example and not to be construed as limiting the scope of the invention.

What I claim as my invention is:

1. In a device of the character described, a frame, journal boxes supported in fixed spaced axial alignment in said frame, the inner ends of said journal boxes having axially aligned bores therethrough and each having a cylindrical chamber coaxial with said bores, and of greater diameter than said bores, extending outwardly therefrom, opening in the outer ends of said journal boxes, said bore and chamber of each journal box defining an inner end wall in a diametrical plane, a driven shaft extending through said journal boxes and therebeyond. having an intermediate portion of a diameter to fit said bores and end portions of reduced diameter adapted to carry grinding wheels, defining at the point of diametrical reduction annular shoulders in a diamet-rical plane, the length of said intermediate portion being. such that said shoulders lie in the planes of said inner end walls, a bearing fitting within the chamber of each journal box and about the reduced portion of said shaft,.positioned against the; inner end wall of said chamber and the adjacent shoulder on said shaft, a dust seal for each journal box comprising a wide cylindrical metal annulus fitting within said chamber and about the reduced portion of said shaft, positioned against said bearing, the outer face of said annulus being flush with the outer end of said journal box, said journal boxes-being divided into matching halves in an axial plane of said shaft, one-half of each being a pillow block in fixed relation to said frame, the other half being a removable cap, said cap and pillow block having parallel aligned holes on opposite sides of said shaft to receive securing bolts, the holes in said pillow blocks being threaded, said dust seal having parallel boreson opposite sides, registerable with said bolt holes, and securing bolts in said bolt holes and bores screwed into said pillow block for immobilizing said dust seal against rotation and endwise movement.

2. In a device of the character described as claimed in claim. 1, said bearings each being a ballbearing with inner and outer races, the inner race overlying the interfacial joint between the adjacent end of the journal box and the shaft.

3. In a device of the character described as claimed in claim 1, the plane of division between the matching halves of the. journal boxes bein intersected by dowels projecting from one-half into pits. in the other half, the pattern ofdowels and pits being nonidentical for the respective S journal boxes, rendering the caps nonlnter- Number changeable with respect to the pillow blocks. 560,214 JOHN E. BERNARD, JR. 983,993 1,243,661 REFERENCES CITED 5 1,190,258 The following references are of record in the 1373-338 file of this patent: UNITED STATES PATENTS 2,288,579 Number Name Date :0 2,482,934

470,497 Loveland et a1. Mar. 8, 1892 6 Name Date Hyde May 19, 1896 Graef Feb. 14, 1911 Harrison Oct. 16, 1917 Alden et a1 July 11, 1916 Isom Dec. 18, 1923 Ritz, Jr. Dec. 12, 1933 Merrigan Aug. 25, 1936 Anesi June 30, 1942 Rambolt et a1. Sept. 2'7, 1949 

